This disclosure relates generally to thermal controls for an electrical storage device in a vehicle. More particularly, the present disclosure relates to a system and method for heating the electrical storage device.
Electric and hybrid electric vehicles have become increasingly popular to meet the demand for fuel-efficient, environmentally-friendly transportation. Such vehicles often include an electrical storage device, such as a high-voltage traction battery, for powering an electric motor to drive the vehicle, either alone or in conjunction with an internal combustion engine, fuel cell engine, or other prime mover.
Currently available electric and hybrid electric vehicles tend to operate more effectively in moderate and warm climates and less effectively in extremely cold climates. This is because high voltage traction batteries tend to lose power as battery cell temperature drops (e.g., below approx. 20° C.). This power decrease results in reduced vehicle performance, fuel economy and drivability. At extremely low temperatures, the traction battery may have insufficient power to even start the vehicle.
Maintaining a proper battery temperature is desirable to ensure optimal vehicle performance in many different climates. Sustaining the battery temperature at a desired level can be challenging because the battery temperature can be affected by many factors, such as the battery condition, the battery cell temperature, the battery charge condition when the vehicle is turned off, and the ambient temperature. Self-powered battery heaters are able to maintain a minimum battery temperature level only for short time periods because the amount of power available for heating is limited by the storage capacity of the battery itself. Thus, self-powered battery heaters are unsuitable when the battery needs to be heated for an extended time period and/or when the battery needs to be warmed to a higher temperature to ensure optimal vehicle performance.
As such, there is a need for a system that can maintain a battery temperature to a level that ensures reliable starting of an electric or hybrid vehicle. There is also a need for a system that can maintain a proper battery temperature in a controlled manner to ensure optimum vehicle performance.